Combat Arms is a Korean game, part of a cluster of online shooters that feature realistic, if not true-to-life, weapons, and have a focus on acquiring better weapons through repeated play.

In an online profile associated with the "Kaynbred" username, the extent of Lanza's obsession with the game becomes clear: he played 4,901 matches. Match lengths of the game are variable, but taking a conservative estimate of 5 minutes per match would mean that Lanza played 410 hours of the game, or 17 full days. The real total is likely much higher.

In context, his dedication to the game is chilling. "Kaynbred" had 83,496 kills, among them, 22,725 headshots.

The weapon "loadout" that "Kaynbred" used the last time he played the game resembles strongly the weapons that he used to kill 27 people in December of last year. His preferred "primary" weapon, the M16A3, is a military variant of the Bushmaster AR-15 assault rifle that Lanza used. His preferred "secondary" weapon, the G23 pistol, strongly resembles Lanza's Glock 10mm handgun. He used these guns to kill an average of 17 people per match.

is almost entirely indoors and is set in a seemingly abandoned secret facility. Featuring multiple levels, this map contains many tightly spaced areas, so combat is centered in Close-Quarters Battle . As a result of this, using Explosives can cause utter chaos for everyone in the game. Sniper Rifles can be rendered ineffective by the close quarters, so assault rifles , machine guns , and Submachine guns are mainly used.

These statistics, in the context of the game, are not unusual for a dedicated player; in fact, Lanza was not "ranked" according to the official game hierarchy. But in the context of Lanza's other online activity — obsessive edits to mass murder Wikipedia entries and frequent activity on gun forums — the sheer amount of time spent playing a game this focused on purchasing realistic weapons and using them to kill, is chilling.